X-ray CT apparatus and image processing apparatus

Abstract

According to one embodiment, an X-ray CT apparatus includes an generation unit, detection unit, processing unit, and reconstruction unit. The generation unit irradiates an object with X-rays. The detection unit includes detection elements corresponding to a plurality of channels, which output detection signals upon detecting X-rays. The processing unit smoothes projection data constituted by numerical values corresponding to signals output from the elements so as to more strongly smooth a portion exhibiting a larger amount of change in the numerical value. The reconstruction unit reconstructs an image by using a plurality of projection data smoothed by the image processing unit.

What is claimed is: 
     
       1. An X-ray CT apparatus comprising:
 an X-ray generation unit configured to irradiate an object with X-rays; 
 an X-ray detection unit including X-ray detection elements corresponding to a plurality of channels, which are arrayed in a predetermined direction to output detection signals upon detecting X-rays transmitted through the object; 
 an image processing unit configured to smooth projection data constituted by numerical values corresponding to detection signals output from the X-ray detection elements corresponding to the plurality of channels so that for all values of a change in the numerical value in a channel direction, the greater the change in the numerical values in the channel direction, the greater a smoothing strength to the projection data; and 
 a reconstruction unit configured to reconstruct an image by using a plurality of projection data smoothed by the image processing unit. 
 
     
     
       2. The X-ray CT apparatus of  claim 1 , wherein the image processing unit smoothes the projection data by applying a Gaussian filter to the projection data so that the greater the change in the numerical values in the channel direction, the greater a variance value. 
     
     
       3. The X-ray CT apparatus of  claim 1 , wherein the image processing unit smoothes the projection data by uniformly smoothing the projection data and adding the each of the numerical values included in the uniformly smoothed projection data and corresponding numerical values included in the projection data so that the greater the change in the numerical values, the smaller a weight to the projection data. 
     
     
       4. An image processing apparatus comprising:
 an image processing unit configured to smooth projection data constituted by numerical values corresponding to detection signals output when X-ray detection elements corresponding to a plurality of channels, which are arrayed in a predetermined direction, detect X-rays transmitted through an object, so that for all values of a change in the numerical value in a channel direction, the greater the change in the numerical values in the channel direction, the greater a smoothing strength to the projection data; and 
 a reconstruction unit configured to reconstruct an image by using a plurality of projection data smoothed by the image processing unit. 
 
     
     
       5. The image processing apparatus of  claim 4 , wherein the image processing unit smoothes the projection data by applying a Gaussian filter to the projection data so that the greater the change in the numerical values in the channel direction, the greater a variance value. 
     
     
       6. The image processing apparatus of  claim 4 , wherein the image processing unit smoothes the projection data by uniformly smoothing the projection data and adding the each of the numerical values included in the uniformly smoothed projection data and corresponding numerical values included in the projection data so that the greater the change in the numerical values, the smaller a weight to the projection data.